The present invention relates to ducting of cooling air to a radiator or heat exchanger for the engine and hydraulic system of an excavator that changes the flow of inlet cooling air to the radiator to reduce noise from the engine at the exterior of an excavator cab.
It is common in power equipment to have the cooling air inlet into the engine directly aligned with the radiator or heat exchanger used for cooling the coolant of an internal combustion engine, and also for cooling hydraulic oil used for operating components. In small excavators, in particular this opening that is close to the engine compartment. This tends to raise the level of ambient noise in the cab and outside of the excavator cab during operation.
Various sound attenuating engine enclosures have been advanced, such as those shown in U.S. Pat. Nos. 3,762,489 and 3,960,238, where insulation layers or baffles are used in connection with attenuating material to reduce engine noise.
An efficient flow pattern for cooling air is shown in U.S. Pat. No. 4,815,550, in connection with a skid steer loader.
The present ducting system arranges the incoming air intakes and ducting on the rotating platform of an excavator to provide adequate airflow and to reduce exterior noise.
The present invention relates to an inlet air duct for an engine powered machine that is positioned so that the air inlet is at a location remote from the engine compartment. The opening at the engine compartment wall to the heat exchanger or radiator for the engine is not directly open on a straight path to the outside, but is through a duct that causes the airflow to change direction as it enters the radiator. This provides a solid wall facing the opening to the engine compartment, so that sound generated by the engine and engine cooling air fan or blower does not pass directly to the exterior and is also reduced in the operator cab. The opening or openings for the inlet air then can be facing in directions that are not adjacent the sides of the machine cab, and can be facing in directions that are not normally in line with persons standing near the excavator, and are more remote from an operator as well.
Specifically, on an excavator, which is shown in the specification, the engine is mounted in a housing at the rear portion of the operator cab structure. The operator""s compartment is at a forward portion and is separated from the engine compartment by a wall. The inlet air duct is positioned to open to the normal laterally facing opening leading to the heat exchanger or radiator, and engine compartment but it extends along the side of the cab to a remote inlet opening that preferably faces either forwardly toward the boom, or downwardly to face toward the support frame or tracks of the excavator so that the air inlet openings do not directly emit sound waves toward areas where people would normally stand.
The ducts are formed to provide for a smooth flow of air so that adequate cooling air is provided by the fan. Not only is engine noise reduced but fan noise is also reduced in that the opening that the fan faces is a solid wall of the duct, and does not direct sound waves directly laterally of the cab. The sound level for the operator is also reduced by directing the sounds to locations remote from the cab.